Used polymer plastics have high fuel values (approximately 40MJ/kg for polyolefines). Therefore, they constitute perfect energy materials. Thermodestruction of used products and wastes of polymer plastics on specialized installations seems to be a long-term method to manage this group of wastes in chemical recycling with the destination to obtain fuel ingredients. Application of this technology allows for reduction the quantity of municipal waste. This enables also to obtain the valuable fuel components. In the Department of Environment Chemistry and Technology of Institute of Chemistry at the University of Silesia and in enterprises using the installation for the thermodestruction of used polymer plastics it was studied influence of different catalyst on course of thermodestruction. According to an innovatory technology elaborated in the enterprise called oSperanda-1o Sp. z o.o. the dirty used products of polymer plastics and wastes after melting flow down to the bottom part of the reactor, where they undergo thermal degradation due to a contact with the catalyst. It was ascertained that type of catalyst influences the course of the primary and secondary destruction processes and is of fundamental importance for capacity of this process and for the composition of the obtained products.